WordNet sense 1 (suck or take up or in):

take in

WordNet sense 2 (take up, as of debts or payments):

take over

WordNet sense 3 (take in, also metaphorically):

draw, imbibe, suck, take up, sop up, suck up, soak up

WordNet sense 4 (take up mentally):

assimilate, ingest

WordNet sense 5 (engross (oneself) fully):

engross, engulf, immerse, plunge, steep

WordNet sense 6 (engage or engross wholly):

engage, occupy